Amorphous silicon (α-Si) technology and low-temperature polysilicon (LTPS) technology are widely used in the field of display technology. With the development of display technology, the LTPS technology is increasingly widely used due to the advantages of high efficient and high definition.
A magnitude of leakage current is an important parameter for the LTPS structure. The high magnitude of leakage current may cause a driving voltage to be unable to maintain at a certain level and may result in undesirable display performance. A dual-gate or multi-gate structure is currently used as a method for reducing the leakage current of the LTPS structure, for example, the dual-gate structure including two gates 7 shown in FIG. 1 is used. Although an electric field distribution in a channel may be effectively reduced by using the plurality of gates so that hot carrier effect is reduced and the leakage current is restrained, the gate 7 is generally made of metal material with good electrical conductivity, e.g., molybdenum or molybdenum aluminum alloy, and the material (i.e., the gate 7 in FIG. 1) itself is opaque and will block the light. Therefore, the technical solution of utilizing the structure of dual-gate or multi-gate in the prior art goes against improvement of display aperture ratio.